You can always find those constants by calling EntityClassList["AdministrativeDivision"].

You can also use ctrl + =, for example "us states + DC" gives EntityClass["AdministrativeDivision", "AllUSStatesPlusDC"].

Thanks, Alan. When I tried the code this morning it failed in the first cell with the error "EntityValue::ctimeout: A computation timed out." I still get the error, however it worked for me just now. I find the syntax and constants a bit mysterious. Can you recommend some documentation that covers the usages in your reply?

Thanks again and best regards,

David

Ok, seems to be working now though very slow... hard to understand the instability of all of this...

OK DavidR and AlanC...this code seems to work for me now...

stateNames = 
 StringJoin@(Capitalize /@ 
      StringSplit[StringReplace[#, "," -> ""]][[;; -3]]) & /@ (#[
      "Name"] & /@ 
    EntityList[
     EntityClass["AdministrativeDivision", "AllUSStatesPlusDC"]])

counties = 
  Flatten[EntityList[
      EntityClass["AdministrativeDivision", "USCounties" <> #]] & /@ 
    stateNames];

Length@counties

income = EntityValue[counties, 
   EntityProperty["AdministrativeDivision", "MedianHouseholdIncome"]];

Length@income

GeoRegionValuePlot[Rule @@@ Transpose[{counties, income}], 
 GeoRange -> 
  EntityClass["AdministrativeDivision", "ContinentalUSStates"]]

I had suppressed output since that was in Alan's sample code. Now, unsuppressed, it looks like Mma V10.0 (Home) Win8,1 also comes back unevaluated from that command.

Hacking through this... I had to do this some while ago, but can't find the code.. here is something that works:

stateNames = 
 StringJoin@(Capitalize /@ 
      StringSplit[StringReplace[#, "," -> ""]][[;; -3]]) & /@ (#["Name"] & /@ 
    EntityList[
     EntityClass["AdministrativeDivision", "AllUSStatesPlusDC"]])

And then

counties = Flatten[
  EntityList[
     EntityClass["AdministrativeDivision", "USCounties" <> #]] & /@  stateNames];

(Deconstruct this from the inside out to see the reasons for each step) This then gives

Length[counties]  -> 3143

Querying Wolfram Alpha on this number, it gives 3144. Exercise for the interested student (that's not me!): why is there a missing county?

In[26]:= counties = 
  EntityList[
   EntityClass["AdministrativeDivision", 
    "ParentRegion" -> 
     EntityClass["AdministrativeDivision", "AllUSStatesPlusDC"]]];

In[28]:= income = 
  EntityValue[counties, 
   EntityProperty["AdministrativeDivision", "MedianHouseholdIncome"]];

In[30]:= GeoRegionValuePlot[Rule @@@ Transpose[{counties, income}], 
 GeoRange -> 
  EntityClass["AdministrativeDivision", "ContinentalUSStates"]]

1. Based on this link (), I have been avoiding the XXXData[] objects in favor of the EntityXXX[] classes. If this is the approach you have to take with Entity[]s, maybe their design is not suited for problems like this. Of course, doing this with SQL is trivial

2. There are some challenges to accomplish what you are seeking. I hope that the method below is either not the most efficient and/or it will be improved going forward.

I did not try the approach of downloading all of the (hundred thousand plus) administrative divisions. Based on some examples, I did the following:

• asked W|a for a list of states
• fed this list into Interpreter[] to get the state Enitity[]s
• fed the list of states back into W|a to get a list of counties, for each state
• fed this list into Interpreter[] to get the county Enitity[]s <<< there are problems with this (i.e. Hamilton County, Ohio was returned by Interpreter[])
• got the list of administrative division properties to find the desired properties
• (* next is do the work to crunch the data together...not done because of the next bullet *)

I can guess that bringing all AdministrativeDivisions into memory would fail on some machines.

1. Further, I found a lot of the properties have missing data when querying for counties. The data is much more prevalent when querying for states. Of course both are AdministrativeDivisions and thus have the same set of properties.

The code (in the Notebook) attached is just a sketch of how this method could be accomplished. A full application could be created from this sketch.

Attachments: